Bicycle handlebar-fork clamp assembly

ABSTRACT

A rear housing has a vertical bore for receipt of a bicycle fork tube and a horizontal bore for receipt of a movable piston slightly longer than the length of the horizontal bore. A front housing has a concave rear portion cooperating with a concave front portion of the rear housing to form a gripping enclosure for a bicycle handlebar. Threaded bores in the front housing are aligned axially with threaded bores in the rear housing so that tightening down on the front housing to the rear housing with threaded bolts causes the handlebar to be gripped tightly and the movable piston is urged backwardly to tightly hold the fork tube.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a clamp assembly for joining a bicyclehandlebar to a fork tube. More particularly, it refers to a movablepiston inside a clamp joining a bicycle handlebar to a fork tube.

[0002] Most bicycle manufacturers employ a split clamp design to jointhe handlebars to the fork tube. This involves splitting a fork clampand using bolts or screws to construct the handlebar stem around thefork tube. The stem is secured to the fork by tightening splitfasteners.

[0003] Typical prior art methods and assembly devices for securinghandlebars to a fork tube are shown in U.S. Pat. Nos. 5,193,930;5,373,757; 5,536,102; 5,881,606 and 6,309,135. None of these prior artmethods and assembly devices provide a simple one step method of joininga bicycle handlebar to its fork tube employing a movable piston. Such aone step method is needed to simplify bicycle construction and repair.

SUMMARY OF THE INVENTION

[0004] The above problem is solved with a three piece clamp assembly. Arear housing has a vertical bore for receipt of a fork tube and ahorizontal bore enclosing a movable piston, the piston being slightlylonger than the horizontal bore. A front housing has a rear concaveportion that together with a front concave portion of the rear housinggrips a bicycle handlebar when the front housing is attached to the backhousing by multiple bolts connecting the front housing and a frontportion of the rear housing. As the bolts are tightened, the piston ismoved backwards to tightly engage the fork tube.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The invention can be best understood by those having ordinaryskill in the art by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings in which:

[0006]FIG. 1 is an exploded view of the clamp assembly of thisinvention.

[0007]FIG. 2 is a perspective view of the clamp assembly prior tojoining a handlebar to a fork tube.

[0008]FIG. 3 is a sectional view along line 3-3 of FIG. 2.

[0009]FIG. 4 is an elevational side view of a bicycle mounting ahandlebar to a fork tube with the inventive clamp assembly.

[0010]FIG. 5 is a sectional view of the clamp assembly connecting thebicycle handlebars to the fork tube shown in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

[0011] Throughout the following detailed description, the same referencenumerals refer to the same elements in all figures.

[0012] The clamp assembly 10 of this invention shown in FIGS. 1 and 2,has a rear housing 12, a movable hollow piston 14 and a front housing16, together with multiple bolts 18 to fasten the clamp assemblycomponents over a bicycle handlebar 20 and fork 22 shown in FIGS. 4 and5.

[0013] The rear housing 12 has a vertical bore 24 through a top surface26 and a bottom surface 28. A horizontal bore 38 begins at anintersection with bore 24 and continues through to a concave surface 30on a front portion of housing 12. Planar surfaces 32 and 34 at a frontface of the housing 12 each has two threaded horizontal bores 50 on eachside for receipt of threaded bolts 18. Decorative depressions 36 areformed on all sides of rear housing 12.

[0014] The hollow piston 14 is movable within bore 38 of rear housing12, and is slightly longer than bore 38. The piston 14 has a concaverear end 40 and a concave front end 42.

[0015] Front housing 16 has a concave 44 rear portion and planarsurfaces 46 and 48 that align with planar surfaces 32 and 34 on rearhousing 12. Each planar surface 46 and 48 has threaded bores 52 on eachside. Bores 52 are axially aligned with bores 50 when bolts 18 areinserted to tighten the clamp assembly 10. When the clamp assembly 10 istightened together forward edges 54 and 56 at the leading front edge ofpiston 14 is stopped by back wall portions 60 and 58 respectively onfront housing 16.

[0016] When joining a bicycle handlebar to a bicycle fork, a horizontalportion 62 of handlebar 20 is placed between rear housing 12 and fronthousing 16 in opening 64 and the bolts 18 are lightly tightened. Thebore 24 is then occupied by the fork 22 and the bolts 18 are tighteneddown to force piston 14 to exert pressure on both fork 22 and handlebarportion 62 to lock them in position.

[0017] The clamp components are made from high strength aluminum, orsteel.

[0018] Equivalent components can be substituted for the components setforth herein to accomplish substantially the same function insubstantially the same way to create substantially the same result.

Having described the invention, what is claimed follows:
 1. A bicycleclamp assembly for joining a bicycle handlebar to a fork tube, theassembly comprising: a rear housing having a vertical through bore toaccommodate the fork tube, a horizontal bore directed forward from thevertical through bore to a partially concave front portion of the rearhousing, the front portion of the rear housing having a planar frontface above and below the concave front portion, and a movable pistonwithin the horizontal bore; a front housing having a partially concaverear portion and a planar rear face above and below the concave rearportion, the planar rear face containing threaded bores axially alignedwith the threaded bores in the rear housing; and multiple bolts forjoining the front housing to the rear housing.
 2. The clamp assemblyaccording to claim 1 wherein the movable piston is hollow and has aconcave front and rear surface.
 3. The clamp assembly according to claim1 wherein the rear face of the front housing and the front face of therear housing are a pair of planar faces axially aligned.
 4. Method ofmounting a bicycle handlebar to a fork tube comprising: providing aclamp assembly having a vertical through bore in a rear housing andinserting a top portion of the fork tube through the vertical throughbore; providing a horizontal bore in the rear housing, the horizontalbore directed forward from the fork tube to a concave front portion ofthe rear housing and a pair of planar front faces above and below theconcave front portion on the rear housing, the planar surfacescontaining threaded bores and positioning a movable piston in thehorizontal bore; providing a front housing having a concave rear portionand a pair of planar rear faces above and below the concave rearportion, the planar rear faces having multiple threaded bores axiallyaligned with the threaded bores in the rear housing; and inserting ahorizontal portion of the handlebar between the front and rear housingand tightening down on multiple threaded bolts in the threaded bores tocause the handlebar to be gripped between the concave surfaces of thefront and rear housing and causing the piston to press against the forktube to hold it in position.